Biostimulation of crude oil-polluted soils: influence of initial physicochemical and biological characteristics of soil

摘要

Biostimulation of the activity of degrading autochthonous microbiota constitutes one of the most accepted bioremediation tools for oil-polluted soils. Applications of nutrients such as nitrogen fertilizers, oleophilic fertilizers or surfactants are some of the strategies employed. Soil microcosm experiments were performed in open glass containers to compare the biological activity of two types of soils: a sandy soil with low nutrient content and low biological activity and a clay loam soil with high nutrient content and high biological activity. Arabian crude oil was used as the contaminant, applied at 10,000mgkg(-1) and 20,000mgkg(-1). Different treatments were used including natural attenuation, used as a control, and the application of different biostimulation products. The results showed that for sandy soil at high hydrocarbon pollution, amendment with oleophilic fertilizer combined with a surfactant was the best treatment, whereas at low hydrocarbon pollution no significant differences were found among the treatments. In clay loam soil, at 10,000mgkg(-1) of hydrocarbon pollution, surfactant application was the most efficient treatment for total petroleum hydrocarbons removal. However, when Arabian crude oil was supplied at 20,000mgkg(-1), nitrogen, phosphorous, and potassium treatment and the oleophilic fertilizer S200C in combination with surfactant treatment presented the highest rate of total petroleum hydrocarbons removal. Thus, the suitability of biostimulation treatments was strongly influenced by the initial physicochemical and biological characteristics of the soil.